UK urges caution over nanotechnology
created by the emerging nanotechnology industry has not been fully
assessed, write Anthony Fletcher and Phil Taylor.
In its report, the UK's Health and Safety Executive (HSE) identified approximately 2,000 people in the UK currently working in universities, research centres and new nanotechnology companies who could potentially be exposed to nanoparticles in some form.
But while 500 workers are considered to be potentially exposed to nanoparticles through existing ultrafine manufacturing processes, mostly the manufacture of carbon black, around 100,000 individuals may be exposed to fine powders through various powder handling processes.
Nanotechnology is concerned with the production and control of materials and objects on the nanoscale, which is, to say the least, small. One nanometer is the same as one millionth of a millimetre.
The attraction of the technology is that new materials and processes, with functions and properties that cannot be achieved otherwise, can in principle be made through the accurate control at this atomic and molecular level. Some scientists envisage nano-size factories in the future.
A recent study from Helmut Kaiser Consultancy, which looked into nanotechnology in the food industry estimated that the nanofood market will surge from $2.6 billion today to 20.4 billion in 2010, as the industry begins to realise the potential benefits.
According to packaging consultancy Pira, these include the manufacture of film that will remain transparent, providing the materials are kept smaller than half a micrometer.
And of course, a clear film can be important in the presentation and saleability of certain food products.
However, the HSE report urges caution. It notes that the four main nanoparticle production processes are gas-phase, vapour deposition, colloidal and attrition, all of which could result in exposure through inhalation, dermal or ingestion routes.
Worryingly, the HSE states that no information is available concerning workers' exposure to nanoparticles in the UK, but information from other powder handling processes suggests that exposures may be significant.
"In summary, we conclude that there is little evidence to suggest that the exposure of workers arising from the production of nanoparticles has been adequately assessed," it states.
Key knowledge gaps identified in the study include the absence of agreed definitions or descriptions for nanoparticles or nanoparticle aerosols, and these should define a size interval to take account of the distribution in sizes likely to be present, to consider whether the definition should be based on physical dimensions (e.g. length, diameter, surface area) or on some behavioural property such as diffusivity and take account of agglomerated aerosols.
Progress in this area will be best achieved by building consensus, and the HSE has organised a workshop this month to address these concerns.
Other outstanding issues include a lack of tools to measure nanoparticle exposure in the workplace, little information on adequate control measures and a lack of data for risk assessments.
A copy of the 111-page report can be downloaded from the HSE website.
The safety of nanotechnology has been under scrutiny for some time. It first emerged in the 1980s when Eric Drexler, senior research fellow of the Molecular Engineering Research Institute in the US and a long-standing researcher in the area of nanoscale machines, published a book warning of self-replicating nanomachines that could go out of control - crating what has now become the infamous 'grey goo'.
Drexler has since revised his stance - now maintaining that self-replicating machines are unnecessary to advance the field - but other studies have since warned of different dangers, focusing on the impact of nanoparticles entering the body.
